Accelerator of vulcanization



Patented 'Jan. 23, 1940 UNITED 'sTAres j AGOELERAT a or vULoA'maA'rioN Joy G. Lichty, aw, ohiojassignor to Wing-foot Corporation, Wilmington, Del. a corporation of Delaware No Drawing. Application jl l'overnber 27 1934, Serial No. 755,022. In Canada November-14,

This invention relates to a new-class of compounds'the members of which are valuable either as such or'with othersubstances, in the Vulcan ization of rubber. It relates, among other things, to a method of accelerating the processes of vulcanization by incorporating in the unvulcanized stock certain chemical compounds which notonly are comparatively easy to prepare but also impart desirable physical properties to the vulcanized products. The compounds with which the invention'deals'are new in themselves. and carbonyl may"be-- described as hydrocarbon oxy alkylesters of dithiocarbamic acids. :Illustrative of the compounds which the vention concerns is the type formula I wherein X is a hydrocarbon radical suchasan ethyl, benzyl, p-chlorflphenyl or phenyl radical,

D is an N-substituted thio carbamyl group, n is 7 one or two; and R isa substitutedmethane group. In generah these compounds are prepared by reacting an ester. of an alpha halogen-substituted fatty acidwith a soluble salt, of an riff-substituted dithiocarbamate. Usually it is neces only. to ring together sol tions of' these twjo eagents, In -some case however, it maybenecessaryto allow the mixture of the solutions to stand fora few hours or to heat this mixture slightly. In any case theuproductwforms as. a solid or oil which may be easily separated and purified. The reaction is found to proceed with substantially equal facility with either amonofior' di halo genated fatty acid ester. 2 I}: l In thewformula given above, R represents any substituted methane group. Where theJfatty acid employed is aceticacidpR; is --CI-I2; or:=CH-'-; similarly, where butyric acid, for instance, is employed, R is a propyl group such as .It will be noted that for Rto be a substituted 'methanegroup the one or two halogen atoms are attached to the carbon atom alpha to the carbonyl group of "the halogenated fatty acid ester. It will also be understood that X may be a substltuted hydrocarbon radical as well asan unsubstituted hydrocarbon radical.. ;In the type formula, D is more specifically the group .Inthe. la ter group, R1 and Rz'may be like or unlike radicals or, if desired, R1 and R2 maybe taken together to form a cyclic. alkylene .chain which may, if desired, be interrupted by anoxy- .age'n io'r sulphuratom Als'o,-feither R1 0 R2 but not both, may be hydrogen. .1. 1.::...;

20 Claims. 101. 250-7193) Illustrative of the preparation of these compounds is that of ethyl carboxy methyl di(diethyl dithioca'rbamate) which may be prepared by refluxing on a. steam bath for approximately two hours a mixture-containing 39.3 grams mol) ofethyl dichloro acetate, 444 grams of an aqueous solution containing mol of sodium diethyldiing mol of ethyl dichloroacetate, mol of sodium dimethyl-dithiocarbamate in aqueous solution and 200 cc. of acetone is refluxed for one half hour. Theproduct iscooled and the solid removed by filtration. The yield is about 66%.

When: recrystallized from asolution of chloro- 1 form and alcohol, the product melts at 1'78 degrees C. The reaction is believed to be as fol- Other compounds of the invention are ethyl c arboz ry methyl penta methylene dithiocarbamate, ethyl carboxy methyl; di(penta methylene dithio'carbamate) methyl carboxy methyl dibutyl dithiocarbamate, methyl carboxy methyl di(di iso butyldithioca'rbamate) butyl carboxy methyl diethyl ridithiocarbamate; butyl carboxy methyl N-methyl cyclohexyl dithiocarbamate, butyl carboxy-methyl di(N-methyl phenyl dithiocarbamate), 'iso propyl carboxy methyl dibenzyl dithiocarbamate, iso propyl carboxy methyl di(di iso amyl dithiocarbamate); iso propyl carboxy methyl N-ethyl cyclohexylv dithiocarbamate, cyclohexyl carboxy methyl di(beta phenyl ethylene) dithiacarbamate; cyclohexyl carboxy methyl di(penta methylene dithiocarbamate) hexahydro tolylcarboxy methyl (di(hexahydro tolyl) dithiocarbamate, hexahydro tolyl carboxy methyl di(dibenzyl dithiocarbamate), decahydro naphthyl carboxy-methyl di(diethyl dithiocarbamate); benzyl carboxy methyl di(di tetrahydro-alpha furfuryl dithiocarbamate) beta phenyl ethylene carboxy methyl di(dimethyldithiocarbamate) isobutyl carboxymethyl di(dicyclohexyl dithiocarbamate), iso amyl carboxy methyl di(penta methylene dithiocarbarnate), iso amyl carboxy methyl penta methylene dithiocarbam ate, phenyl carboxy methyl di(diethy1 dithiocarbamate), naphthyl carboxy methyl di(pent a,=

dithiocarbamate) o, m, or p-ethoxy phenyl carthe following: I

boxy methyl di(di amyl dithiOcarbamatelpand o, m, or p-methoxy phenyl" carboxy methyl di,dibenzyl dithiocarbamate) erhamat ethyl e phaca b y propyl 1 ty dithiocarbamate), benzyl alpha carbpxy propyl diethyl dithiocarbamate, eyclohexyl alpha carh y n opyl diidib nzyl dit io erb me m t a pha carb xy pr pyl gi clo exvl d thie erheme ate. bu a p ca boxy pr p th l d} 1 carbamate, and the like. 1

T e p und t which he. v nt o re t s ay e em lo d a a ce er t r f vul an zati n inrsub t n ia n o t ta d r ber r mulae. o ound p rt cularly .a i5 9 9I -P i 1 arts by wei ht Extracted pale crepe rubher nn 199 Zinc oxide 5 Ph Stearic acid 1.5 Accelerator ..0.5

made up gave the following resultsi Stress in kgs./ CR1? Max. 'cmJJ ,Ult. tens. .elong. inkgslcnifi e 'Timein .Temp., percent :,500% 700% Wel i 9 5%. 2 2%.-

arr-1Y1. almost llmser'eleiseeei DITHIOOARBAMATE) nrrnyr. .c iRB 0X5?- .MhiTHXl. DI(l)IMETHYL DITHIQCARBAMATE) 260 52 8 75 8. 20 260 108 845 15 260 156 780' 24. .95 0 a as Th e m und n w i them e ves. pos ess valuable properties as accelerators of :;vulg: an iz a tion. They maybe employed either by themselves or in conjunction with other basic organic nitrogen containing accelerators,v such. as diphenylguanidine, diortho tolyl. guanigline, cro: tonylidene aniline, .diphenylguanidine oxalate, diphenylguanidine succinate and .the;=like.,u-In general, the dihalogen fatty acidlderivatives. of thedithiocarbamates are more powerful than the mono halogen derivatives. Consequently withthe dihalogen derivatives, activators willnot usually :be necessary,although they may-be :found desir able in certain instances. With the'mono halogen derivatives, on the other'hand, activators are. in most .cases .desirable, although not invariably necessary. r This application is, in .part a continuation of application Serial No; 603,454, filed April 5,1932, now Patent No.2,067,494. I

Others are ethyl alpha carboxy propyl penta methylene dithio- .and cyclic .thio .alkylene chains.

in the presence. of- Jethyllcarboxy methyl'di (.diethyl It is intended that the application shall covei', by suitable expression in the appended claims, all features of patehtabl'e novelty residing in the invention.

1. The process which comprises vulcanizing a vulca n'iz abl'e rubber mix in the presence of ethyl carhoxy methyl d iidiethyl dithiocarbamate).

.2. The process wh ich comprises vulcanizing a process vi-hich comprises vulcanizing a j vulcanizable rubher mix in the presence of an ethyl carboxy methyl bamate) -.4.;The process ,which comprises vulcanizing a vnlcanizable rubber mix in the presence of ah-ydrccarbon oxy, carbonyl methyl ester of a dithiocarbamic acid. i

I5.'The process which comprise vulcanizin a vulcanizable rubber mix in the presenceof a compound having the formula di (dialkyl dithiocaree eei eea wherein X is a hydrocarbon radical, D'is' an Nesub'stituted thiocarbamyl .group,"R. is selected from the group consisting of methane radicals and hydrocarbon substituted methane radicals andnis oneor two. M v. 1

6. The process which comprises vulcanizing a. vulcanizable rubber mix in the presence of a compound having th'e' form la .0 L(D.-B).. R:i J:.0:.X wherei is e ls ra cal. R is se e m the group consisting of' met 1. a... i ..x': 2

ea e L i .eee in el c eei ii i i e e d wherein X is an alkyl radical and R1 and R2 are selected from the group consisting of aliphatic hydrocarbon radicals and, R1 and R2 vtogether, 10,

acyclic .alkylene chains, cyclic. oxy alkylene chains I 1110...A rubber product that has been vulcanized dithiccarbamate) Y 16.

wherein X is a hydrocarbon radical, R is selected from the group consisting of methane radicals and hydrocarbon substituted methane radicals, D is a thiocarbamyl group and n is one or two.

14. A rubber product that has been vulcanized in the presence of a compound having the formula wherein X is an alkyl radical, R is selected from the group consisting of methane radicals and hydrocarbon substituted methane radicals, D is an N-substituted thiocarbamyl group and n is one or two.

15. A rubber product that has been vulcanized in the presence of a compound having the formula wherein Y is a tertiary aliphatic amino group and X is alkyl.

16. A rubber product that has been vulcanized in the presence of a compound having the formula R; s 0 ma netron wherein X is an alkyl radical and R1 and R2 are selected from the group consisting of aliphatic hydrocarbon radicals and, R1 and R2 together, cyclic alkylene chains, cyclic oxy alkylene chains and cyclic thio alkylene chains.

1'7. Ethyl carboxy methyl di(diethy1 dithiocarbamate).

18. A compound having the formula 0 (D-s).-R- ;-0x wherein X is a hydrocarbon radical, R is selected from the group consisting of methane radicals and hydrocarbon substituted methane radicals, D is a thiocarbamyl group and n is one or two.

19. A compound having the formula wherein Y is a tertiary aliphatic amino group and X is alkyl.

20. An alkyl carboxy methyl di(N-alkylated dithiocarbamate) JOY G. LICH'I'Y. 

